How Long Does It Take To Get A Decision About An SSDI Claim?
The average time from filing a claim to an initial Social Security decision is 90 - 120 days. The time can be shorter, or much longer.
If you have a condition that qualifies for what Social Security calls a "Compassionate Allownace" - the claim goes much faster. For a list of conditions that qualifyfor Compassionate Allowance, see: http://www.socialsecurity.gov/compassionateallowances/
The more complete your documentation when you file your claim, and the more effort you make to get a speedy, correct result, the more likely the money will start flowing to you in a shorter period of time.
Keep in mind you have no access to the money until there's a positive decision from Social Security -- and Social Security does not pay interest.